The hypothalamus can be considered as the locus within the brain for the integration and control of homeostasis. The objective of this research project is to understand the role of environmental and genetic influences on the development of neurons in the hypothalamus which are involved in endocrine regulation. Alterations in hormone levels during critical periods of development produce major deficits in endocrine regulation in the adult, suggesting that environmental influences during development can have long-term effects on hypothalamic neuronal survival and function. Major environmental influences during development include cell/cell interactions, soluble trophic and growth factors, and alterations in neuronal membrane potential. This research uses dissociated cell cultures of hypothalamus as a simplified model system in which the growth and development of hypothalamic neurons can be observed and quantified. Neuronal survival and growth in culture are measured using quantitative computer-based morphometric techniques, while the synthesis of gene products is measured using biochemical and immunocytochemical techniques. Alterations in these parameters as a result of making discrete alterations in the neuronal environment in culture will provide insight into the role of these influences. in normal hypothalamic development.